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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
  1. GRB 070521: Swift detection of a burst
  2. GRB 070520A: MITSuME Akeno optical upper limits
  3. GRB 070520B, Swift-BAT refined analysis
  4. GRB 070520A, Swift-BAT refined analysis
  5. GRB 070520A: Swift-XRT refined analysis
  6. GRB 070518: TNG observations
  7. GRB 070520B: Swift detection of a burst
  8. GRB 070520: Xinglong EST optical Upper Limit
  9. GRB 070520: Swift detection of a burst
  10. VLA observation of GRB 070518
  11. GRB 070518: Swift-XRT refined analysis
  12. GRB 070517: Gemini optical imaging
  13. GRB070518: UVOT refined analysis
  14. GRB070518: OSN observation
  15. GRB 070518, Swift-BAT refined analysis
  16. GRB 070518: OT confirmed form Xinglong TNT observation
  17. GRB 070518: Swift detection of a burst with optical afterglow
  18. GRB070517: Swift-XRT Refined Analysis
  19. GRB 070517, Swift-BAT refined analysis
  20. GRB 070517: Optical search
  21. GRB 070517: Swift detection of a burst
  22. GRB 070509: objects inside XRT error circle
  23. GRB 070512: pseudo-z ~ 1.39 from prompt emission spectrum
  24. GRB 070512: IPN localization and Konus spectrum of a bright burst
  25. GRB070419A: optical observations
  26. GRB 070419A, Deep LBT photometry
  27. GRB 070508: pseudo-z from 4 different spectral analyses
  28. GRB 070509: Swift/UVOT Upper Limits
  29. Konus-Wind and Konus-A observation of GRB 070508
  30. Swift-BAT trigger 278987 is not a GRB
  31. GRB 070510: Swift detection of a possible burst
  32. GRB070509: Swift-XRT Refined Analysis
  33. RHESSI Spectrum of GRB070508
  34. GRB 070508: OA fading and tentative redshift
  35. GRB 070509, Swift-BAT refined analysis
  36. GRB 070508: Suzaku/WAM observation of the prompt emission
  37. GRB 070509: REM observations
  38. GRB 070509: Swift detection of a burst
  39. GRB 070509: ROTSE-III Optical Limits
  40. GRB070508: Swift/UVOT Observations
  41. GRB 070508, SMARTS optical afterglow observation
  42. GRB 070508, Swift-BAT refined analysis
  43. GRB 070508: Multicolor optical observations and possible redshift limit
  44. GRB 070508: Swift-XRT refined analysis
  45. GRB 070508: Optical observation limiting magnitude
  46. GRB 070508: Optical afterglow detection
  47. GRB 070508: REM observations
  48. GRB 070508: TAROT La Silla observatory optical observations
  49. GRB 070508: Swift detection of an intense burst with an optical counterpart
  50. GRB070412: MAGIC telescope GeV observation
  51. Swift-BAT trigger 278809 is not a GRB
  52. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  53. GRB 070506: VLT redshift
  54. GRB070506: Swift/UVOT Observations
  55. GRB070506: Swift XRT refined analysis
  56. GRB 070506, Swift-BAT Refined Analysis
  57. GRB 070506: Swift detection of a burst with optical afterglow
  58. GRB 070412, deep LBT imaging
  59. GRB 070429A: Swift XRT further analysis
  60. GRB070429B: VLT observations
  61. GRB 070429A: optical observations
  62. GRB070429B: position correction
  63. GRB 070309: Swift-XRT afterglow confirmation
  64. GRB070429B: possible host galaxy detection
  65. VLA observation of GRB 070429B
  66. Swift/UVOT observations of GRB070429B
  67. GRB 070429B, Swift-BAT refined analysis
  68. Swift/UVOT observations of GRB070429A
  69. GRB 070429A: Swift XRT refined analysis
  70. GRB 070429A, Swift-BAT refined analysis
  71. GRB 070429A: optical and NIR observations
  72. GRB 070429B: Swift XRT refined analysis
  73. GRB 070429B: ROTSE-III Optical Limits
  74. GRB 070429B: Swift detection of a short burst
  75. GRB 070429: What's the temperature?
  76. GRB 070429: ROTSE-III Optical Limits
  77. GRB 070429: Swift detection of a burst
  78. GRB 070427, Swift-BAT Refined Analysis
  79. LT monitoring of GRB070412
  80. GRB 070427: Swift detection of a burst
  81. GRB 070411, further deep LBT photometry
  82. GRB 070411: Late-time Keck imaging
  83. GRB 070411 : Planned XMM-Newton observation
  84. GRB070419B: Suzaku WAM observation of the prompt emission
  85. GRB 070420, SMARTS optical/IR afterglow observations
  86. GRB 070411, deep LBT photometry
  87. GRB 070420: pseudo-z~1.56 from spectral parameters of the prompt
  88. Konus-Wind observation of GRB 070420
  89. GRB 070411: break in the optical light curve
  90. GRB 070420 Swift-BAT Refined Analysis
  91. GRB070419A: Kuiper Optical detection
  92. GRB070419a: Swift UVOT observations
  93. GRB 070419A: MARGE Observations
  94. GRB 070420: optical rebrightening observed at Mt. John
  95. GRB 070420: Swift XRT refined analysis
  96. GRB070420: Swift UVOT continuing observations
  97. GRB 070411: BART early limit
  98. GRB 070420: Faulkes Telescope South Observations
  99. GBR 070419A: Swift/XRT refined analysis
  100. GRB 070420: TAROT La Silla observatory optical observations

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